Overhead conductor vibration test method based on multi-field coupling

Abstract

The invention relates to the technical field of smart power grids, and provides a multi-field coupling-based overhead conductor vibration test method, which comprises the following steps of: constructing a multi-field coupling test environment, and loading an overhead conductor into the constructed multi-field coupling test environment; applying a multidirectional vibration load to the overhead conductor, and collecting vibration response data of the overhead conductor in real time; and calculating an equivalent stress field and equivalent stress amplitude distribution according to the vibration response data acquired in real time, and evaluating the damage state and residual life of each position of the overhead conductor. According to the overhead conductor vibration test method based on multi-field coupling, complex working conditions can be truly simulated, the test accuracy is improved, high-precision multidirectional vibration load loading is realized, high-resolution data acquisition and synchronization are realized, and the damage state and the residual life are accurately evaluated.

Description

Technical Field

[0001] The present invention relates to the technical field of smart grids, and in particular to an overhead conductor vibration test method based on multi-field coupling. Background Art

[0002] Overhead conductors, a crucial component of power transmission, are exposed to complex natural environments for extended periods of time in practical applications. These conductors are subject to a variety of factors, including wind loads, snow and ice coverage, and their own weight, causing them to vibrate continuously. This vibration is one of the most common forms of overhead conductor failure, manifesting as severe problems such as breakage at conductor junctions and loose strands. This not only impacts power transmission stability but can also lead to major safety incidents. Statistics show that vibration-induced conductor failures account for over 40% of all overhead conductor failures, a problem particularly acute in windy and cold regions.

[0003] To evaluate and improve the vibration resistance of overhead conductors, simulating the vibration behavior of conductors in actual line environments and conducting relevant tests is crucial. These tests can reveal the dynamic response of conductors in complex environments, providing a basis for line design selection and improved design. However, existing conductor vibration test methods have the following shortcomings: 1. Low environmental simulation accuracy: They only simulate single environmental factors (such as wind load or temperature) and fail to replicate the complex operating conditions of multiple fields coupled (wind, ice, temperature, tension, etc.) in actual lines, resulting in significant deviations between test results and actual operating conditions. 2. Low load application accuracy: When applying vibration loads, achieving high-precision loading in multiple directions and frequency bands is difficult. In particular, phase synchronization control of random and swept-frequency waves is insufficient, affecting the authenticity of the vibration response. 3. Data acquisition and analysis are limited: insufficient spatial resolution and temporal synchronization make it difficult to accurately capture the strain, displacement, and temperature distribution at various locations on the conductor. 4. The prediction results have large errors. The evaluation of the equivalent stress field and damage state based on a simplified model fails to fully consider the nonlinear effects under multi-field coupling. The static empirical formula is used to calculate the remaining life, which lacks adaptability to real-time damage rate and dynamic load changes, resulting in a large deviation between the prediction results and the actual life.

[0004] Chinese patent publication number CN113821971A discloses a method and device for monitoring the breeze vibration of overhead conductors. This solution calculates the fatigue damage of the overhead conductors based on their historical dynamic bending strain and wind speed. This fatigue damage is then used to predict the vibration range of the overhead conductors. In practical applications, this solution suffers from the following shortcomings: It lacks real-world active testing, active excitation, and real-time environmental simulation, making it impossible to capture the dynamic response of the conductors under complex operating conditions in real time. The fatigue damage calculation relies solely on linear accumulation of historical wind speed and strain data, which deviates from the actual service environment and results in high prediction errors.

[0005] Chinese patent publication number CN102564717A discloses an overhead conductor galloping test device and method based on end-of-line displacement excitation. This method simulates the galloping of an overhead conductor when subjected to end-of-line displacement excitation along the conductor's direction, studying the galloping behavior under different spans, excitation frequencies, and excitation amplitudes. This approach only simulates end-of-line displacement excitation and does not account for actual environmental factors such as wind load, icing, and temperature fluctuations, resulting in significant differences between the test conditions and actual transmission lines. It also applies only single-directional harmonic excitation (axial displacement) and cannot simulate multi-directional vibrations (such as vertical and torsional vibration) or random wind-induced vibrations, making it difficult to replicate measured galloping behavior. It relies on high-speed cameras to record macroscopic galloping trajectories and lacks the ability to measure microscopic parameters such as strain, temperature, and dynamic tension, making it impossible to quantify the local stress state of the conductor. The excitation frequency and amplitude must be manually preset, with no real-time feedback adjustment mechanism, making it impossible to optimize test parameters based on the conductor's response. By observing the galloping phenomenon alone and failing to establish a fatigue damage model, it is impossible to assess the life loss of the conductor under long-term vibration.

[0006] Therefore, there is an urgent need for a test method that can truly simulate a multi-field coupling environment, accurately load multi-directional vibration loads, collect high-resolution data in real time, and accurately evaluate the damage status and remaining life of the conductor based on this, so as to solve the above technical problems and provide reliable support for the safe operation and optimized design of overhead conductors. Summary of the Invention

[0007] In view of this, in order to overcome the deficiencies of the prior art, the present invention aims to provide an overhead conductor vibration test method based on multi-field coupling.

[0008] The present invention provides an overhead conductor vibration test method based on multi-field coupling, the method comprising: Step S1: construct a multi-field coupling test environment, and load the overhead conductor into the constructed multi-field coupling test environment; Step S2: applying a multi-directional vibration load to the overhead conductor and collecting vibration response data of the overhead conductor in real time; Step S3: Calculate the equivalent stress field and equivalent stress amplitude distribution based on the real-time collected vibration response data, and evaluate the damage status and remaining life of each position of the overhead conductor.

[0009] Optionally, the present invention is based on a multi-field coupled overhead conductor vibration test method. In step S1, a multi-field coupled test environment is constructed by configuring a programmable wind field generating system, an icing simulation system and a temperature control system in a controllable environment cabin. In the multi-field coupled environment, the overhead conductor is loaded through a dynamic tension loading system, a dynamic tension load is applied to the loaded overhead conductor, a wind load is applied to the overhead conductor through the programmable wind field generating system, an icing load is applied to the overhead conductor through the icing simulation system, and a temperature load is applied to the overhead conductor through the temperature control system.

[0010] Optionally, the present invention is based on a multi-field coupled overhead wire vibration test method, wherein the programmable wind field generating system includes an array variable frequency fan and a wind field homogenization device, the wind field homogenization device includes a honeycomb guide plate and a turbulence generator; the icing simulation system includes a low-temperature spray device and an icing thickness monitoring unit; the temperature control system includes a semiconductor refrigeration module and a resistance heating module; the dynamic tension loading system includes a servo hydraulic actuator, a force sensor and a clamp.

[0011] Optionally, in the overhead conductor vibration test method based on multi-field coupling of the present invention, in step S2, a multi-directional vibration load is applied to the overhead conductor in the following manner: Multiple electromagnetic exciters are used to generate sine wave, random wave and swept wave vibration signals in the frequency range of 0.1-100Hz. The phase difference of multiple electromagnetic exciters is controlled within ±0.5° through a phase synchronization controller. A mechanical vibrator is used to apply vibration perpendicular to the conductor axis according to a preset amplitude curve, and the displacement error of the mechanical vibrator is controlled within 0.1mm through servo motor control; A closed-loop feedback system is used to adjust the amplitude, frequency and direction of the vibration load in real time based on the collected vibration response data.

[0012] Optionally, in the overhead conductor vibration test method based on multi-field coupling of the present invention, in step S2, the vibration response data of the overhead conductor is collected in real time by the following method: The axial strain data of the overhead conductor is measured by an embedded fiber Bragg grating sensor array with a spatial resolution of 1 cm. A three-dimensional laser Doppler vibrometer was used to collect the lateral displacement of the overhead conductor with a resolution of 0.1 μm and time-stamped synchronously with the axial strain data; An infrared thermal imager with a temperature resolution of 0.5°C is used to record the surface temperature distribution of the overhead conductor every 10 seconds, and the recorded temperature data is aligned with the axial strain data through a unified clock signal.

[0013] Optionally, in the overhead conductor vibration test method based on multi-field coupling of the present invention, step S2 further includes: adjusting the parameters of the multi-directional vibration load in real time according to the collected vibration response data.

[0014] Optionally, the overhead conductor vibration test method based on multi-field coupling of the present invention, step S3, includes: Establishing a spatial coordinate system, mapping the collected vibration response data to the established spatial coordinate system to obtain a spatiotemporal dataset, and performing filtering on the spatiotemporal dataset to obtain a preprocessed vibration response dataset; The equivalent stress at each location of the overhead conductor is calculated based on the vibration response data set, and the equivalent stress amplitude at each location is extracted using the time window analysis method. The cumulative damage of each position of the overhead conductor is calculated using the Miner linear cumulative damage method, and the remaining life corresponding to each position is calculated based on the cumulative damage at each position.

[0015] Optionally, in the overhead conductor vibration test method based on multi-field coupling of the present invention, in step S3, the equivalent stress at each position of the overhead conductor is calculated as follows:

[0016] in, For overhead wires Location E is the equivalent stress at the moment, E is the elastic modulus of the overhead conductor, For overhead wires Location The axial strain at time is the thermal expansion coefficient of the overhead conductor, For overhead wires Location The temperature of the moment, is the standard reference temperature.

[0017] Optionally, in the overhead conductor vibration test method based on multi-field coupling of the present invention, in step S3, the equivalent stress amplitude of the overhead conductor is calculated using a time window analysis method in the following manner: -

[0018] in, For overhead wires The equivalent stress amplitude at the position, For overhead wires Location The equivalent stress at time, The range is the time window length.

[0019] Optionally, in the overhead conductor vibration test method based on multi-field coupling of the present invention, in step S3, the remaining life of each position of the overhead conductor is calculated as follows: =

[0020] in, For overhead wires the remaining lifetime of the position, For overhead wires The cumulative damage at the location, is the main vibration frequency, For overhead wires Real-time damage rate of the location.

[0021] The overhead conductor vibration test method based on multi-field coupling of the present invention has the following beneficial technical effects: 1. Realistically simulate complex working conditions to improve test accuracy By integrating programmable wind fields, icing simulation, temperature control and dynamic tension loading systems, a multi-physics field coupling test environment is constructed. This can simultaneously simulate the combined effects of wind, ice, temperature and mechanical vibration, reproduce the complex working conditions of actual transmission lines, and overcome the limitations of traditional single environment simulations. A combination of array-type variable frequency fans, honeycomb guide plates and turbulence generators is used to achieve precise control of wind speed and turbulence intensity, significantly improving the authenticity of wind vibration tests.

[0022] 2. High-precision multi-directional vibration load loading Combining electromagnetic exciters with mechanical exciters, it supports multiple vibration modes such as sine waves, random waves, and swept frequency waves. The phase synchronization error is controlled within ±0.5°, and the displacement accuracy reaches ±0.1 mm, achieving high-fidelity loading of multi-band and multi-directional vibrations. The closed-loop feedback system adjusts the load parameters (amplitude, frequency, direction) in real time to ensure that the vibration response is consistent with the target working conditions, avoiding over-testing or under-testing problems.

[0023] 3. High-resolution data acquisition and synchronization An embedded fiber Bragg grating sensor array is used to monitor axial strain, combined with a three-dimensional laser Doppler vibrometer to collect lateral displacement, and a unified clock signal is used to synchronize multi-source data to fully capture the dynamic response of the conductor. An infrared thermal imager records the temperature distribution, and combined with ice thickness laser scanning, a coupled analysis of temperature-strain-ice load is realized, providing data support for the study of multi-field action mechanisms.

[0024] 4. Accurately assess damage status and remaining lifespan An equivalent stress field calculation model is constructed, and mechanical strain and thermal stress are comprehensively considered to solve the stress quantification problem under multi-field coupling. The equivalent stress amplitude is extracted based on the time window analysis method, and combined with Miner linear cumulative damage theory and dynamic damage rate calculation, real-time prediction of the remaining life of each position of the conductor is achieved, with the error reduced by more than 40% compared with the traditional static model.

[0025] 5. Engineering application value It can provide a basis for optimizing anti-vibration design for transmission line designs, guiding hardware selection, tension setting, and the development of anti-galloping measures. Early damage warnings support dynamic adjustments to operation and maintenance strategies, extending conductor service life and reducing the risk of line breaks.

[0026] The present invention solves the problems of environmental simulation distortion, data acquisition limitations, and large life prediction errors in existing test methods through multi-field coupling environment construction, high-precision load loading, multi-dimensional data fusion and dynamic life assessment, providing reliable technical support for the safe operation and intelligent operation and maintenance of overhead conductors. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the following briefly introduces the drawings required for use in the embodiments. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0028] Figure 1 is a flow chart of an overhead conductor vibration test method based on multi-field coupling according to an exemplary embodiment of the present invention; Figure 2 2. A layout diagram of a test device for an overhead conductor vibration test method based on multi-field coupling according to an exemplary embodiment of the present invention; In the figure, 1- variable frequency fan, 2- honeycomb guide plate, 3- turbulence generator, 4- overhead wire, 5- low temperature spray device, 6- laser rangefinder, 7- weighing sensor, 8- semiconductor refrigeration module, 9- resistance heating module, 10- servo hydraulic actuator, 11- force sensor, 12- fixture, 13- sensing optical fiber, 14- fiber Bragg grating sensor, 15- electromagnetic exciter, 16- mechanical exciter, 17- phase synchronization controller, 18- main vibrometer, 19- auxiliary vibrometer, 20- main thermal imager, 21- auxiliary thermal imager. DETAILED DESCRIPTION

[0029] The embodiments of the present invention are described in detail below with reference to the accompanying drawings.

[0030] It should be noted that, in the absence of conflict, the following embodiments and features in the embodiments may be combined with each other; and, based on the embodiments in this disclosure, all other embodiments obtained by persons of ordinary skill in the art without creative work are within the scope of protection of this disclosure.

[0031] It should be noted that various aspects of the embodiments within the scope of the appended claims are described below. It should be apparent that the aspects described herein can be embodied in a wide variety of forms, and any specific structure and / or function described herein is merely illustrative. Based on this disclosure, it should be understood by those skilled in the art that an aspect described herein can be implemented independently of any other aspect, and two or more of these aspects can be combined in various ways. For example, any number of aspects described herein can be used to implement an apparatus and / or practice a method. In addition, other structures and / or functionalities other than one or more of the aspects described herein can be used to implement this apparatus and / or practice this method.

[0032] An exemplary embodiment of the present invention provides an overhead conductor vibration test method based on multi-field coupling, Figure 1 FIG. 1 is a flow chart of a vibration test method for an overhead conductor based on multi-field coupling according to an exemplary embodiment of the present invention. Figure 1 As shown, the overhead conductor vibration test method based on multi-field coupling of this embodiment is implemented in the following manner: Step S1: construct a multi-field coupling test environment, and load the overhead conductors into the constructed multi-field coupling test environment.

[0033] As an optional example, this embodiment constructs a multi-field coupling test environment by configuring a programmable wind field generation system, an icing simulation system, and a temperature control system within a controllable environmental chamber. In this multi-field coupling environment, overhead conductors are loaded with a dynamic tension loading system, and dynamic tension loads are applied to the loaded overhead conductors. Wind loads are applied to the overhead conductors via the programmable wind field generation system, ice loads are applied to the overhead conductors via the icing simulation system, and temperature loads are applied to the overhead conductors via the temperature control system.

[0034] In this embodiment, the programmable wind field generation system includes an array of variable-frequency fans and a wind field homogenization device, which includes a honeycomb deflector and a turbulence generator. The array of variable-frequency fans is used to simulate natural wind spectra, including average and pulsating winds. It communicates with the master control PLC via the Modbus RTU protocol to implement programmed wind field patterns such as gusts and step winds. The honeycomb deflector is installed downstream of the fan outlet to convert the fan's rotating airflow into a uniform direct current. The turbulence generator is driven by a servo motor to generate controllable turbulence and replicate the wind field characteristics of the atmospheric boundary layer.

[0035] For example, in actual applications, the array-type variable-frequency fan of this embodiment is composed of multiple EBM-Papst RadiCal centrifugal variable-frequency fans of model R3G500-AN05-01, with a single-unit power of 5.5kW, a wind speed adjustment range of 0.5-25 m / s, stepless frequency conversion control, a resolution of 0.1 m / s, a wind pressure range of 200-1500Pa, and turbulence intensity adjustable in the range of 5-30%, thereby covering the full range of working conditions from overhead wire breeze vibration (0.5-5m / s) to dancing (greater than 8m / s).

[0036] For example, in practical applications, the honeycomb deflector of this embodiment is made of an aluminum honeycomb core material with a pore size of 10mm and an aspect ratio of 1:1.5. Installed 0.5m downstream of the fan outlet, covering an area of ​​2m×2m, it converts the fan's swirling airflow into a uniform direct current with a wind speed distribution unevenness within ±3%. The turbulence generator is an active grid-type device with an adjustable grid spacing between 50 and 200mm. In practical applications, the grid can be driven by a servo motor to rotate 0-30°, generating controllable turbulence with a turbulence integral scale of 0.1-5m.

[0037] In this embodiment, the icing simulation system includes a low-temperature spray device and an ice thickness monitoring unit. The low-temperature spray device is composed of an atomizing nozzle, a cooling system, and a water supply system. The ice thickness monitoring unit is composed of a laser rangefinder and a weighing sensor.

[0038] For example, a Spraying Systems 1 / 4J atomizing nozzle and a liquid nitrogen direct cooling system are used. The nozzle's flow rate is 0.5-3 L / min, and the droplet size is 20-50 μm. In the liquid nitrogen direct cooling system, -196°C liquid nitrogen is depressurized and mixed with deionized water, with an outlet temperature adjustable from -30°C to 0°C. The liquid nitrogen injection rate is adjusted using PID control, and the spray temperature is controlled with an accuracy of ±0.5°C, achieving spray coverage of over 95% on the conductor surface.

[0039] For example, in actual application, eight Keyence LK-G5000 laser rangefinders with a measurement range of 50-500mm and a resolution of 0.001mm are used in a circular array, scanning the conductor circumference at 45° intervals. A load cell, HBMU9B, with a range of 100kg and an accuracy of ±0.02%FS, is installed at the conductor suspension end to measure the mass change per unit length in real time. In this embodiment, the ice thickness of the overhead conductor is calculated as follows:

[0040] in, is the ice thickness of the overhead wire; For the The diameter of the wire (including ice) measured by a laser rangefinder; is the initial diameter of the overhead conductor (without ice); is the ice shape correction factor, which is 0.9 for smooth rime ice and 0.7 for loose rime ice; is the mass per unit length of the conductor after ice coating; is the initial mass per unit length of the conductor (ice-free state); is the density of ice, rime is 900kg / m 3 , rime is 600kg / m 3 ; is the effective length of the overhead conductor being measured.

[0041] In this embodiment, the temperature control system includes a semiconductor cooling module and a resistance heating module. For example, in actual application, a semiconductor cooling module model TEC1-12706 (maximum cooling power 72W, ΔTmax = 68°C) is used, with 20 modules connected in parallel. The cold end uses a 10mm thick copper vapor chamber with a thermal conductivity of 398W / m·K for heat conduction. Power is regulated using a 1kHz PWM frequency, achieving a temperature gradient control accuracy of ±0.3°C / m. The resistance heating module includes a heating element made of nickel-chromium alloy wire with a total power of 8kW and a temperature sensor. The heating element is arranged in zones within the environmental chamber.

[0042] In this embodiment, the dynamic tension loading system includes a servo-hydraulic actuator, a force sensor, and a fixture. For example, a Moog G122-302A servo-hydraulic actuator is used, with a maximum output of 50 kN, a travel range of ±100 mm, a -3 dB bandwidth of 15 Hz (sine wave), and a step response time of 5 ms. The hydraulic source is a constant-pressure variable pump with a pressure of 21 MPa and a flow rate of 30 L / min. The accuracy in force-controlled mode is ±0.5% FS, and the resolution in displacement-controlled mode is 1 μm. The HBM S9M force sensor is used, with a 50 kN range, a nonlinearity of <0.01%, a temperature compensation range of -30°C to +70°C, a 24-bit ADC sampling rate, and an anti-aliasing filter cutoff frequency of 1 kHz. In this embodiment, the fixture utilizes a wedge-shaped clamping structure with a self-tightening, anti-slip design (made of 42CrMo, HRC 45-50 hardness).

[0043] Step S2: applying multi-directional vibration loads to the overhead conductors, and collecting vibration response data of the overhead conductors in real time.

[0044] As an optional example, this embodiment uses multiple electromagnetic exciters to generate sinusoidal, random, and swept-frequency vibration signals within a frequency range of 0.1-100 Hz, and controls the phase difference of the multiple electromagnetic exciters to within ±0.5° through a phase synchronization controller. In actual applications, the electromagnetic exciter is directly fixed to the end fixture of the conductor test section, parallel to the conductor axis. A mechanical exciter is used to apply vibration perpendicular to the conductor axis according to a preset amplitude curve, and the displacement error of the mechanical exciter is controlled to within 0.1 mm through servo motor control. In actual applications, the mechanical exciter is connected to the mid-span position of the conductor (1 / 2 the span length from the end) through a rigid connecting rod, and the application direction is perpendicular to the conductor axis. A closed-loop feedback system is used to adjust the amplitude, frequency, and direction of the vibration load in real time based on the collected vibration response data.

[0045] As an optional example, this embodiment collects the vibration response data of the overhead wire in real time by the following method: The axial strain data of the overhead conductor is measured by an embedded fiber Bragg grating sensor array with a spatial resolution of 1 cm.

[0046] In this embodiment, the embedded fiber Bragg grating sensor array is arranged as follows: the sensing optical fiber is embedded in the outermost strand of the overhead conductor along the axial direction of the conductor, a measurement point is set every 0.5m, and a reinforced fiber Bragg grating sensor with a measurement range of ±5000με is set at the connection between the overhead conductor and the clamp.

[0047] A 3D laser Doppler vibrometer is used to collect lateral displacements of overhead conductors with a resolution of 0.1 μm and synchronize the time stamps with the axial strain data. In practice, the primary vibrometer is mounted on an adjustable height bracket directly above the conductor, vertically aligned at the conductor midspan (1-2 m from the conductor, depending on the focal length), to capture lateral galloping and axial vibration. Auxiliary vibrometers are positioned symmetrically on either side of the conductor (at a 45° angle to the conductor), covering the end region, to monitor torsional vibration and local modes.

[0048] An infrared thermal imager with a temperature resolution of 0.5°C records the surface temperature distribution of the overhead conductor every 10 seconds. This recorded temperature data is aligned with the axial strain data using a unified clock signal. The primary infrared camera is mounted 3-5 meters to the side of the conductor (its field of view covers the entire test section), with an adjustable pitch angle of 30-60° to avoid interference from water mist in the icing simulation system. An auxiliary infrared camera is positioned near the conductor end clamp to monitor temperature anomalies at the clamp contact point.

[0049] It should be noted that, in this embodiment, the parameters of the multi-directional vibration load are adjusted in real time according to the collected vibration response data.

[0050] Step S3: Calculate the equivalent stress field and equivalent stress amplitude distribution based on the real-time collected vibration response data, and evaluate the damage status and remaining life of each position of the overhead conductor.

[0051] As an optional example, in this embodiment, first, a spatial coordinate system is established, the collected vibration response data is mapped to the established spatial coordinate system to obtain a spatiotemporal dataset, and the spatiotemporal dataset is filtered to obtain a preprocessed vibration response dataset.

[0052] Then, the equivalent stress at each location of the overhead conductor is calculated based on the vibration response data set, and the equivalent stress amplitude at each location is extracted using the time window analysis method.

[0053] In this embodiment, the equivalent stress at each position of the overhead conductor is calculated as follows:

[0054] in, For overhead wires Location E is the equivalent stress at the moment; E is the elastic modulus of the overhead conductor, calibrated by tensile test; For overhead wires Location The axial strain at each moment is monitored and collected by an embedded fiber Bragg grating sensor array; is the thermal expansion coefficient of the overhead conductor, which is calibrated through thermal expansion test; For overhead wires Location The temperature at each moment is monitored and collected by an infrared thermal imager. is the standard reference temperature; is the axial position coordinate of the overhead wire.

[0055] In this embodiment, the equivalent stress amplitude is a key parameter used to quantify the fatigue damage of the conductor under the combined action of multi-axial complex loads such as vibration, temperature, and icing. The multi-directional and multi-type loads in actual working conditions are converted into an equivalent uniaxial alternating stress amplitude so that the fatigue characteristics data of the material can be directly applied for life prediction.

[0056] As an optional example, this embodiment uses a time window analysis method to calculate the equivalent stress amplitude of the overhead conductor in the following manner: -

[0057] in, For overhead wires The equivalent stress amplitude at the position, For overhead wires Location The equivalent stress at time, The range is the time window length, is the axial position coordinate of the overhead conductor. In practical applications, [ ], is one or more vibration cycles, To monitor the initial time.

[0058] Then, the cumulative damage of each position of the overhead wire is calculated using the Miner linear cumulative damage method, and the remaining life corresponding to each position is calculated based on the cumulative damage of each position.

[0059] The remaining service life of each position of the overhead conductor is calculated as follows: =

[0060] in, For overhead wires the remaining lifetime of the position, For overhead wires The cumulative damage at the location, is the main vibration frequency, For overhead wires Real-time damage rate of the location, is the axial position coordinate of the overhead wire.

[0061] In this embodiment, For overhead wires The cumulative damage of a location indicates the current damage status of the location and is calculated as follows:

[0062] in, For location Place Stress levels The number of cycles that actually work; For location Place Stress levels The number of cycles to failure under the action of a single factor (fatigue life); is the total number of divided stress levels, i.e., the discretization The number of intervals, is the axial position coordinate of the overhead conductor. It should be noted that, in this embodiment, Determined by the following modified Coffin-Manson equation:

[0063] In this embodiment, For overhead wires The real-time damage of the position, that is, the rate of change of the cumulative damage amount over time under the current load conditions, is used to quantify the damage development speed, reflect the immediate degradation trend of the wire at a specific vibration frequency, stress amplitude and temperature, and dynamically update the remaining life. In this embodiment, It is calculated as follows: =

[0064] in, For overhead wires The cumulative damage at the location, is the time step, Current stress level The corresponding fatigue life (number of cycles), The main vibration frequency.

[0065] Figure 2 According to an embodiment of the present invention Figure 2 FIG. 1 is a layout diagram of a test device for an overhead conductor vibration test method based on multi-field coupling according to an exemplary embodiment of the present invention. Figure 2 As shown, in this embodiment, a programmable wind field generating system consisting of a variable frequency fan 1, a honeycomb deflector 2 and a turbulence generator 3 is distributed in an array around the overhead conductor 4 to be detected; the icing simulation system includes a low-temperature spray device 5, a plurality of laser rangefinders 6 and a weighing sensor 7, the laser rangefinders 6 are distributed in a circular array along the axis of the overhead conductor 4, and the weighing sensor 7 is installed at the hanging end of the overhead conductor 4; the temperature control system includes a plurality of parallel semiconductor refrigeration modules 8 and a plurality of resistance heating modules 9 distributed on both sides of the overhead conductor 4 to be detected; the dynamic tension loading system includes a servo hydraulic actuator 10, a force sensor 11 and a clamp 12, and a dynamic tension load is applied to the loaded overhead conductor 4 through the dynamic tension loading system to simulate the force under different gear spacings; a sensing optical fiber 13 is arranged along the axial direction of the overhead conductor 4, and a fiber grating sensor 14 is arranged at the connection between the overhead conductor 4 and the clamp 12. The electromagnetic exciter 15 is fixed on the fixture 12 and is axially parallel to the overhead conductor 4. The mechanical exciter 16 is connected to the mid-span position of the overhead conductor 4 through a rigid connecting rod. A phase synchronization controller 17 is set between the electromagnetic exciter 15 and the mechanical exciter 16; the main vibrometer 18 of the three-dimensional laser Doppler vibrometer is fixed directly above the overhead conductor 4, and the auxiliary vibrometers 19 are arranged symmetrically on both sides of the overhead conductor 4; the main thermal imager 20 of the infrared thermal imager is installed on the side of the overhead conductor 4, and the auxiliary thermal imager 21 of the infrared thermal imager is set near the fixture 12 at the end of the overhead conductor 4.

[0066] The following further describes in detail the overhead conductor vibration test method based on multi-field coupling in this embodiment in a specific scenario: The specimens in this scenario used LGJ-400 / 35 steel-core aluminum stranded conductors. Vibration tests were conducted in a multi-field coupled test system that simulated actual operating conditions to accurately assess their dynamic response, damage state, and remaining life. The specimen parameters used are shown in Table 1 below. The test system configuration is shown in Table 2 below.

[0067] Table 1

[0068] Table 2

[0069] The experimental process of this scenario is as follows: 1. Initialize the test environment: Conductor installation: Fix both ends of the conductor to the dynamic tension loading system and apply an initial tension of 10 kN (25% of the rated breaking force).

[0070] Environmental parameter settings: Wind field: average wind speed 8m / s, turbulence intensity 15% (simulating natural wind conditions).

[0071] Icing: Spray temperature -10℃, target ice thickness 5mm.

[0072] Temperature: Environmental chamber temperature -5°C (simulating working conditions in high-altitude cold areas).

[0073] 2. Multiple vibration loads: Electromagnetic exciter: 5-30Hz random wave vibration, ±0.3° phase synchronization control error; Mechanical exciter: ±5mm (perpendicular to the conductor axis), amplitude ±0.08mm displacement control accuracy; Closed-loop feedback adjustment: Dynamically adjust the excitation parameters based on real-time strain data (target ±1000με).

[0074] 3. Data collection, see Table 3 below.

[0075] Table 3

[0076] 4. Equivalent stress calculation: Take the midpoint of the wire ( =5m) = Data at 60s: Axial strain =800με, temperature =-5℃, the equivalent stress is: =14.625Mpa.

[0077] 5. Extraction of equivalent stress amplitude: In the time window [ ], maximum stress: =18.2MPa, minimum stress =10.1MPa, the equivalent stress amplitude is =18.2-10.1=8.1MPa.

[0078] 6. Cumulative damage and remaining life prediction: The fatigue life is determined by the modified Coffin-Manson equation:

[0079] in, =500MPa (fatigue strength coefficient), =-0.1 (fatigue strength index), =0.5 (fatigue ductility coefficient), =-0.6 (fatigue ductility index), substitute =8.1MPa, technetium solution, =1.2×10 5 Second cycle. Cumulative damage: Current loop count =5000 times: = =0.0417.

[0080] Remaining life: Main vibration frequency =20Hz, real-time damage rate: = 20=1.67×10 -4 s -1 ; = == =287 hours.

[0081] Wire midpoint ( =5 m) in a simulated multi-field coupling environment, the cumulative damage was 4.17%, and the remaining life was approximately 287 hours. High-stress areas (such as those near the suspension points) require special monitoring, and it is recommended to adjust the operation and maintenance strategy based on the real-time damage rate.

[0082] The overhead conductor vibration test method based on multi-field coupling according to an embodiment of the present invention has the following beneficial technical effects: 1. Realistically simulate complex working conditions to improve test accuracy By integrating programmable wind fields, icing simulation, temperature control and dynamic tension loading systems, a multi-physics field coupling test environment is constructed. This can simultaneously simulate the combined effects of wind, ice, temperature and mechanical vibration, reproduce the complex working conditions of actual transmission lines, and overcome the limitations of traditional single environment simulations. A combination of array-type variable frequency fans, honeycomb guide plates and turbulence generators is used to achieve precise control of wind speed and turbulence intensity, significantly improving the authenticity of wind vibration tests.

[0083] 2. High-precision multi-directional vibration load loading Combining electromagnetic exciters with mechanical exciters, it supports multiple vibration modes such as sine waves, random waves, and swept frequency waves. The phase synchronization error is controlled within ±0.5°, and the displacement accuracy reaches ±0.1 mm, achieving high-fidelity loading of multi-band and multi-directional vibrations. The closed-loop feedback system adjusts the load parameters (amplitude, frequency, direction) in real time to ensure that the vibration response is consistent with the target working conditions, avoiding over-testing or under-testing problems.

[0084] 3. High-resolution data acquisition and synchronization An embedded fiber Bragg grating sensor array is used to monitor axial strain, combined with a three-dimensional laser Doppler vibrometer to collect lateral displacement, and a unified clock signal is used to synchronize multi-source data to fully capture the dynamic response of the conductor. An infrared thermal imager records the temperature distribution, and combined with ice thickness laser scanning, a coupled analysis of temperature-strain-ice load is realized, providing data support for the study of multi-field action mechanisms.

[0085] 4. Accurately assess damage status and remaining lifespan An equivalent stress field calculation model is constructed, and mechanical strain and thermal stress are comprehensively considered to solve the stress quantification problem under multi-field coupling. The equivalent stress amplitude is extracted based on the time window analysis method, and combined with Miner linear cumulative damage theory and dynamic damage rate calculation, real-time prediction of the remaining life of each position of the conductor is achieved, with the error reduced by more than 40% compared with the traditional static model.

[0086] 5. Engineering application value It can provide a basis for optimizing anti-vibration design for transmission line designs, guiding hardware selection, tension setting, and the development of anti-galloping measures. Early damage warnings support dynamic adjustments to operation and maintenance strategies, extending conductor service life and reducing the risk of line breaks.

[0087] In summary, the present invention solves the problems of environmental simulation distortion, data acquisition limitations, and large life prediction errors in existing test methods through multi-field coupling environment construction, high-precision load loading, multi-dimensional data fusion, and dynamic life assessment, providing reliable technical support for the safe operation and intelligent operation and maintenance of overhead conductors.

[0088] The above description is merely a specific embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any changes or substitutions that can be easily conceived by a person skilled in the art within the technical scope disclosed in the present invention should be included in the scope of protection of the present invention. Therefore, the scope of protection of the present invention should be based on the scope of protection of the claims.

Claims

1. A vibration test method for overhead conductors based on multi-field coupling, characterized in that: The method comprises: Step S1: construct a multi-field coupling test environment, and load the overhead conductor into the constructed multi-field coupling test environment; Step S2: applying a multi-directional vibration load to the overhead conductor and collecting vibration response data of the overhead conductor in real time; Step S3: Calculate the equivalent stress field and equivalent stress amplitude distribution based on the real-time collected vibration response data, and evaluate the damage status and remaining life of each position of the overhead conductor.

2. The overhead conductor vibration test method based on multi-field coupling according to claim 1, characterized in that: In step S1, a multi-field coupling test environment is constructed by configuring a programmable wind field generating system, an icing simulation system and a temperature control system in a controllable environment cabin. In the multi-field coupling environment, the overhead conductors are loaded through a dynamic tension loading system, and a dynamic tension load is applied to the loaded overhead conductors. A wind load is applied to the overhead conductors through the programmable wind field generating system, an icing load is applied to the overhead conductors through the icing simulation system, and a temperature load is applied to the overhead conductors through the temperature control system.

3. The overhead conductor vibration test method based on multi-field coupling according to claim 2, characterized in that: The programmable wind field generation system includes an array of variable frequency fans and a wind field homogenization device, wherein the wind field homogenization device includes a honeycomb guide plate and a turbulence generator; the icing simulation system includes a low-temperature spray device and an icing thickness monitoring unit; the temperature control system includes a semiconductor refrigeration module and a resistance heating module; the dynamic tension loading system includes a servo hydraulic actuator, a force sensor and a clamp.

4. The overhead conductor vibration test method based on multi-field coupling according to claim 1, characterized in that: In step S2, a multi-directional vibration load is applied to the overhead conductor in the following manner: Multiple electromagnetic exciters are used to generate sine wave, random wave and swept wave vibration signals in the frequency range of 0.1-100Hz. The phase difference of multiple electromagnetic exciters is controlled within ±0.5° through a phase synchronization controller. A mechanical vibrator is used to apply vibration perpendicular to the conductor axis according to a preset amplitude curve, and the displacement error of the mechanical vibrator is controlled within 0.1mm through servo motor control; A closed-loop feedback system is used to adjust the amplitude, frequency and direction of the vibration load in real time based on the collected vibration response data.

5. The overhead conductor vibration test method based on multi-field coupling according to claim 1, characterized in that: In step S2, the vibration response data of the overhead conductor is collected in real time by: The axial strain data of the overhead conductor is measured by an embedded fiber Bragg grating sensor array with a spatial resolution of 1 cm. A three-dimensional laser Doppler vibrometer was used to collect the lateral displacement of the overhead conductor with a resolution of 0.1 μm and time-stamped synchronously with the axial strain data; An infrared thermal imager with a temperature resolution of 0.5°C is used to record the surface temperature distribution of the overhead conductor every 10 seconds, and the recorded temperature data is aligned with the axial strain data through a unified clock signal.

6. The overhead conductor vibration test method based on multi-field coupling according to claim 1, characterized in that: Step S2 also includes: adjusting the parameters of the multi-directional vibration load in real time according to the collected vibration response data.

7. The overhead conductor vibration test method based on multi-field coupling according to claim 1, characterized in that: Step S3 includes: Establishing a spatial coordinate system, mapping the collected vibration response data to the established spatial coordinate system to obtain a spatiotemporal dataset, and performing filtering on the spatiotemporal dataset to obtain a preprocessed vibration response dataset; The equivalent stress at each location of the overhead conductor is calculated based on the vibration response data set, and the equivalent stress amplitude at each location is extracted using the time window analysis method. The cumulative damage of each position of the overhead conductor is calculated using the Miner linear cumulative damage method, and the remaining life corresponding to each position is calculated based on the cumulative damage at each position.

8. The overhead conductor vibration test method based on multi-field coupling according to claim 7, characterized in that: In step S3, the equivalent stress at each position of the overhead conductor is calculated as follows: in, For overhead wires Location E is the equivalent stress at the moment, E is the elastic modulus of the overhead conductor, For overhead wires Location The axial strain at time is the thermal expansion coefficient of the overhead conductor, For overhead wires Location The temperature of the moment, is the standard reference temperature.

9. The overhead conductor vibration test method based on multi-field coupling according to claim 7, characterized in that: In step S3, the time window analysis method is used to calculate the equivalent stress amplitude of the overhead conductor in the following manner: - in, For overhead wires The equivalent stress amplitude at the position, For overhead wires Location The equivalent stress at time, The range is the time window length.

10. The overhead conductor vibration test method based on multi-field coupling according to claim 7, characterized in that: In step S3, the remaining life of each position of the overhead conductor is calculated as follows: = in, For overhead wires the remaining lifetime of the position, For overhead wires The cumulative damage at the location, is the main vibration frequency, For overhead wires Real-time damage rate of the location.

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